The Midweight Zip T has been discontinued. It was replaced by the Smartwool Merino 250 Base Layer 1/4 Zip.

If you're looking for something new, check out the best base layer tops for 2020.

photo: Smartwool Midweight Zip T base layer top


Price MSRP: $90.00
Historic Range: $34.83-$105.00
Reviewers Paid: $50.00
Price MSRP: $90.00
Historic Range: $34.23-$110.00
Price MSRP: $55.00
Historic Range: $14.83-$65.00


Previous mountaineers use only strong and waterproof…

Rating: rated 4.5 of 5 stars
Source: received it as a personal gift


Previous mountaineers use only strong and waterproof skins with wool underwear and base layer like for expeditons on Everest after long period of new unnatural wear few years ago some companies start to make wool items back just because this natural material fits better than others.


  • Top and my spouse wear it at Elbrus with joy!


  • Only if you wash in hot and machine wash!

Much luck to all Alpine Climbers and I hope that you share my mining for wool like I do for you all about down items.

When U Climb, Climb Good !

Fact: this top is my favorite piece of clothing. If…

Rating: rated 5 of 5 stars
Fabric: wool
Price Paid: $50

Fact: this top is my favorite piece of clothing. If you look at any of my other reviews you will see that I spend most of my time in that fine, kind, merino. That being said, this top (of which I own 2), is my most used piece of clothing. It doesn't seem to matter if I am hiking with weight in the 60's or stopping for a break in the low 40's. I spend the majority of my clothed life with this shirt on.

The zipper is a huge plus in terms of thermal regulation over the crew. It allows you to open and vent to cool off or zip up and seal off your neck to heat up. It will not smell after days on the trail and will not melt if an ember finds its way to your body. I love this shirt

Where to Buy

Help support this site by making your next gear purchase through one of the links above. Click a link, buy what you need, and the seller will contribute a portion of the purchase price to support Trailspace's independent gear reviews.